In general, a research into a technology in which a secondary battery capable of charging and discharging electricity unlike a primary battery is applied to high technology fields such as a digital camera, a cellular phone, a notebook computer, a hybrid automobile, and the like, has been actively conducted. As the secondary battery, a nickel-cadmium battery, a nickel-metal hydride battery, a nickel-hydrogen battery, and a lithium secondary battery are included.
Among them, the lithium secondary battery has an operation voltage of 3.6V or more to be used as a power supply of a portable electronic device or to be used in high power hybrid automobile by connecting batteries in a series. As compared to the nickel-cadmium battery or the nickel-metal hydride battery, the operation voltage of the lithium secondary battery is three times higher than those of the nickel-cadmium battery or the nickel-metal hydride battery, and energy density properties per unit weight are also excellent, such that the use of the lithium secondary battery has rapidly increased.
The lithium secondary battery is capable of being manufactured so as to have various shapes, and cylindrical type and prismatic type lithium secondary batteries have been usually exemplified for the lithium secondary battery. The lithium polymer battery in the recent spotlighted is manufactured in a pouched type having flexibility, such that the shape thereof is relatively varied. In addition, the lithium polymer battery has excellent stability and light weight, such that it is advantageous for slimness and lightness of a portable electronic device.
FIG. 1 is a view showing a structure of a pouched type lithium secondary battery 1 according to the related art, wherein the conventional pouched type lithium secondary battery 1 includes a battery part 2 and a case 3 providing a space in which the battery part 2 is accommodated.
Meanwhile, in the case in which high power lithium battery such as a hybrid automobile is required, several tens and hundreds of the poached type lithium secondary batteries shown in FIG. 1 are multilayered and connected to each other in series or in parallel, thereby obtaining a high voltage.
As described above, in the case in which a plurality of pouched type lithium secondary batteries are used to configure a middle and large-sized battery module, since a number of members are generally needed for mechanical and electrical connection, a process of assembling those members is significantly complicated. In addition, a space for coupling, welding, and soldering a number of members to each other is required, and accordingly a size of the entire system is increased. The increase in size is not preferred in view of limitation in a space of the system or a device having a middle and large-sized battery module mounted thereon.
Therefore, in order to be effectively mounted in a limited inner space such as an automobile, or the like, a middle and large-sized battery module case having a compact structure in which a number of pouched type lithium secondary batteries are capable of being strongly and stably multilayered, is required.
Further, in the case in which defects occur in a portion of the pouched type lithium secondary battery configuring the middle and large-sized battery module, since a large amount of time and many processes are required in disassembly and assembly processes for overcoming the defects, the battery module case which is easily capable of performing assembly and disassembly processes with a simple structure is highly required.